For users, microkernel technology promises (90) , compact and sophisticated operating systems that are typically (91) across a range of hardware platforms. These operating systems will be customizable to let users run multiple operating system and application "personalities" on top of a single microkernel (92) .
Microkernel based systems can provide this flexibility because the core operating system functions are (93) from the large number of utilities, features and extensions that are layered on top of them. As a result, updating and maintaining operating system is easier, since developers don’t have to modify the (94) every time they must acid a new feature.

A．separate

B．connected

C．compared

D．selected

有防水、防潮要求的地面，宜在防水、防潮隔离层施工完毕并验收（）再铺设绝热层。

A.前

B.后

C.合格后

D.交接